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Diaz-Martinez VD, Cyr M, Devic S, Tomic N, Lewis DF, Enger SA. Investigation of dosimetric characteristics of radiochromic film in response to alpha particles emitted from Americium-241. Med Phys 2024. [PMID: 38767310 DOI: 10.1002/mp.17133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 02/15/2024] [Accepted: 03/15/2024] [Indexed: 05/22/2024] Open
Abstract
BACKGROUND In radiotherapy, it is essential to deliver prescribed doses to tumors while minimizing damage to surrounding healthy tissue. Accurate measurements of absorbed dose are required for this purpose. Gafchromic® external beam therapy (EBT) radiochromic films have been widely used in radiotherapy. While the dosimetric characteristics of the EBT3 model film have been extensively studied for photon and charged particle beams (protons, electrons, and carbon ions), little research has been done on α $\alpha$ -particle dosimetry. α $\alpha$ -emitting radionuclides have gained popularity in cancer treatment due to their high linear energy transfer, short range in tissue, and ability to spare surrounding organs at risk, thereby delivering a more localized dose distribution to the tumor. Therefore, a dose-calibration film protocol for α $\alpha$ -particles is required. PURPOSE This study aimed to develop a dose-calibration protocol for the α $\alpha$ -particle emitting radionuclide 241Am, using Monte Carlo (MC) simulations and measurements with unlaminated EBT3 films. METHODS In this study, a MC-based user code was developed using the Geant4 simulation toolkit to model and simulate an 241Am source and an unlaminated EBT3 film. Two simulations were performed: one with voxelized geometries of the EBT3 active volume composition and the other using water. The dose rate was calculated within a region of interest in the voxelized geometries. Unlaminated EBT3 film pieces were irradiated with the 241Am source at various exposure times inside a black box. Film irradiations were compared to a 6-MV photon beam from a Varian TrueBeam machine. The simulated dose rate was used to convert the exposure times into absorbed doses to water, describing a radiochromic-film-based reference dosimetry protocol for α $\alpha$ -particles. The irradiated films were scanned and through an in-house Python script, the normalized pixel values from the green-color channel of scanned film images were analyzed. RESULTS The 241Am energy spectra obtained from the simulations were in good agreement with IAEA and NIST databases, having differences < $<$ 0.516% for the emitted γ $\gamma$ -rays and produced characteristic x-rays and < $<$ 0.006% for the α $\alpha$ -particles. Due to the short range of α $\alpha$ -particles, there was no energy deposition in the voxels outside the active 241Am source region projected onto the film surface. Thus, the total dose rate within the voxels covering the source was 0.847 ± $\pm$ 0.003 Gy/min within the sensitive layer of the film (LiPCDA) and 0.847 ± $\pm$ 0.004 Gy/min in water, indicating that the active volume can be considered water equivalent for the 241Am beam quality. A novel approach was employed in α $\alpha$ -film dosimetry using an exponential fit for the green channel, which showed promising results by reducing the uncertainty in dose estimation within 5%. Although the statistical analysis did not reveal significant differences between the 6-MV photon beam and the α $\alpha$ calibration curves, the dose-response curves exhibited the expected behavior. CONCLUSIONS The developed MC user code simulated the experimental setup for α $\alpha$ -dosimetry using radiochromic film with acceptable uncertainty. Unlaminated EBT3 film is suitable for the dosimetry of α $\alpha$ -radiation at low doses and can be used in conjunction with other unlaminated GafChromic® films for quality assurance and research purposes.
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Affiliation(s)
- Victor D Diaz-Martinez
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Mélodie Cyr
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Slobodan Devic
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
| | - Nada Tomic
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
| | | | - Shirin A Enger
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
- Research Institute of McGill University Health Centre, Montréal, Québec, Canada
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2
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Bobić M, Christensen JB, Lee H, Choulilitsa E, Czerska K, Togno M, Safai S, Yukihara EG, Winey BA, Lomax AJ, Paganetti H, Albertini F, Nesteruk KP. Optically stimulated luminescence dosimeters for simultaneous measurement of point dose and dose-weighted LET in an adaptive proton therapy workflow. Front Oncol 2024; 13:1333039. [PMID: 38510267 PMCID: PMC10951997 DOI: 10.3389/fonc.2023.1333039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 12/18/2023] [Indexed: 03/22/2024] Open
Abstract
Purpose To demonstrate the suitability of optically stimulated luminescence detectors (OSLDs) for accurate simultaneous measurement of the absolute point dose and dose-weighted linear energy transfer (LETD) in an anthropomorphic phantom for experimental validation of daily adaptive proton therapy. Methods A clinically realistic intensity-modulated proton therapy (IMPT) treatment plan was created based on a CT of an anthropomorphic head-and-neck phantom made of tissue-equivalent material. The IMPT plan was optimized with three fields to deliver a uniform dose to the target volume covering the OSLDs. Different scenarios representing inter-fractional anatomical changes were created by modifying the phantom. An online adaptive proton therapy workflow was used to recover the daily dose distribution and account for the applied geometry changes. To validate the adaptive workflow, measurements were performed by irradiating Al2O3:C OSLDs inside the phantom. In addition to the measurements, retrospective Monte Carlo simulations were performed to compare the absolute dose and dose-averaged LET (LETD) delivered to the OSLDs. Results The online adaptive proton therapy workflow was shown to recover significant degradation in dose conformity resulting from large anatomical and positioning deviations from the reference plan. The Monte Carlo simulations were in close agreement with the OSLD measurements, with an average relative error of 1.4% for doses and 3.2% for LETD. The use of OSLDs for LET determination allowed for a correction for the ionization quenched response. Conclusion The OSLDs appear to be an excellent detector for simultaneously assessing dose and LET distributions in proton irradiation of an anthropomorphic phantom. The OSLDs can be cut to almost any size and shape, making them ideal for in-phantom measurements to probe the radiation quality and dose in a predefined region of interest. Although we have presented the results obtained in the experimental validation of an adaptive proton therapy workflow, the same approach can be generalized and used for a variety of clinical innovations and workflow developments that require accurate assessment of point dose and/or average LET.
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Affiliation(s)
- Mislav Bobić
- Department of Physics, ETH Zurich, Zurich, Switzerland
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | | | - Hoyeon Lee
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Evangelia Choulilitsa
- Department of Physics, ETH Zurich, Zurich, Switzerland
- Paul Scherrer Institute, Villigen, Switzerland
| | | | | | | | | | - Brian A. Winey
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Antony J. Lomax
- Department of Physics, ETH Zurich, Zurich, Switzerland
- Paul Scherrer Institute, Villigen, Switzerland
| | - Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | | | - Konrad P. Nesteruk
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
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3
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Gerard A, Peyrichon M, Vidal M, Barnel C, Sauerwein W, Carnicer A, Angellier G, Mathis T, Mishra K, Thariat J, Herault J. Ocular proton therapy, pencil beam scanning high energy proton therapy or stereotactic radiotherapy for uveal melanoma; an in silico study. Cancer Radiother 2022; 26:1027-1033. [PMID: 35803862 DOI: 10.1016/j.canrad.2022.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 03/23/2022] [Accepted: 03/30/2022] [Indexed: 11/15/2022]
Abstract
PURPOSE In radiotherapy, the dose and volumes of the irradiated normal tissues is correlated to the complication rate. We assessed the performances of low-energy proton therapy (ocular PT) with eye-dedicated equipment, high energy PT with pencil-beam scanning (PBS) or CyberKnifeR -based stereotactic irradiation (SBRT). MATERIAL AND METHODS CT-based comparative dose distribution between external beam radiotherapy techniques was assessed using an anthropomorphic head phantom. The prescribed dose was 60Gy_RBE in 4 fractions to a typical posterior pole uveal melanoma. Clinically relevant structures were delineated, and doses were calculated using radiotherapy treatment planning softwares and measured using Gafchromic dosimetry films inserted at the ocular level. RESULTS Precision was significantly better with ocular PT than both PBS or SBRT in terms of beam penumbra (80%-20%: laterally 1.4 vs. ≥10mm, distally 0.8 vs. ≥2.5mm). Ocular PT duration was shorter, allowing eye gating and lid sparing more easily. Tumor was excellent with all modalities, but ocular PT resulted in more homogenous and conformal dose compared to PBS or SBRT. The maximal dose to ocular/orbital structures at risk was smaller and often null with ocular PT compared to other modalities. Mean dose to ocular/orbital structures was also lower with ocular PT. Structures like the lids and lacrimal punctum could be preserved with ocular PT using gaze orientation and lid retractors, which is easier to implement clinically than with the other modalities. The dose to distant organs was null with ocular PT and PBS, in contrast to SBRT. CONCLUSIONS ocular PT showed significantly improved beam penumbra, shorter treatment delivery time, better dose homogeneity, and reduced maximal/mean doses to critical ocular structures compared with other current external beam radiation modalities. Similar comparisons may be warranted for other tumor presentations.
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Fleury E, Trnková P, Spruijt K, Herault J, Lebbink F, Heufelder J, Hrbacek J, Horwacik T, Kajdrowicz T, Denker A, Gerard A, Hofverberg P, Mamalui M, Slopsema R, Pignol J, Hoogeman M. Characterization of the HollandPTC proton therapy beamline dedicated to uveal melanoma treatment and an interinstitutional comparison. Med Phys 2021; 48:4506-4522. [PMID: 34091930 PMCID: PMC8457201 DOI: 10.1002/mp.15024] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/08/2021] [Accepted: 05/25/2021] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Eye-dedicated proton therapy (PT) facilities are used to treat malignant intraocular lesions, especially uveal melanoma (UM). The first commercial ocular PT beamline from Varian was installed in the Netherlands. In this work, the conceptual design of the new eyeline is presented. In addition, a comprehensive comparison against five PT centers with dedicated ocular beamlines is performed, and the clinical impact of the identified differences is analyzed. MATERIAL/METHODS The HollandPTC eyeline was characterized. Four centers in Europe and one in the United States joined the study. All centers use a cyclotron for proton beam generation and an eye-dedicated nozzle. Differences among the chosen ocular beamlines were in the design of the nozzle, nominal energy, and energy spectrum. The following parameters were collected for all centers: technical characteristics and a set of distal, proximal, and lateral region measurements. The measurements were performed with detectors available in-house at each institution. The institutions followed the International Atomic Energy Agency (IAEA) Technical Report Series (TRS)-398 Code of Practice for absolute dose measurement, and the IAEA TRS-398 Code of Practice, its modified version or International Commission on Radiation Units and Measurements Report No. 78 for spread-out Bragg peak normalization. Energy spreads of the pristine Bragg peaks were obtained with Monte Carlo simulations using Geant4. Seven tumor-specific case scenarios were simulated to evaluate the clinical impact among centers: small, medium, and large UM, located either anteriorly, at the equator, or posteriorly within the eye. Differences in the depth dose distributions were calculated. RESULTS A pristine Bragg peak of HollandPTC eyeline corresponded to the constant energy of 75 MeV (maximal range 3.97 g/cm2 in water) with an energy spread of 1.10 MeV. The pristine Bragg peaks for the five participating centers varied from 62.50 to 104.50 MeV with an energy spread variation between 0.10 and 0.70 MeV. Differences in the average distal fall-offs and lateral penumbrae (LPs) (over the complete set of clinically available beam modulations) among all centers were up to 0.25 g/cm2 , and 0.80 mm, respectively. Average distal fall-offs of the HollandPTC eyeline were 0.20 g/cm2 , and LPs were between 1.50 and 2.15 mm from proximal to distal regions, respectively. Treatment time, around 60 s, was comparable among all centers. The virtual source-to-axis distance of 120 cm at HollandPTC was shorter than for the five participating centers (range: 165-350 cm). Simulated depth dose distributions demonstrated the impact of the different beamline characteristics among institutions. The largest difference was observed for a small UM located at the posterior pole, where a proximal dose between two extreme centers was up to 20%. CONCLUSIONS HollandPTC eyeline specifications are in accordance with five other ocular PT beamlines. Similar clinical concepts can be applied to expect the same high local tumor control. Dosimetrical properties among the six institutions induce most likely differences in ocular radiation-related toxicities. This interinstitutional comparison could support further research on ocular post-PT complications. Finally, the findings reported in this study could be used to define dosimetrical guidelines for ocular PT to unify the concepts among institutions.
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Affiliation(s)
- Emmanuelle Fleury
- Department of RadiotherapyErasmus MC Cancer Institute, University Medical Center RotterdamThe Netherlands
- Holland Proton Therapy CenterDelftThe Netherlands
| | - Petra Trnková
- Department of RadiotherapyErasmus MC Cancer Institute, University Medical Center RotterdamThe Netherlands
- Departement of Radiation OncologyMedical University of ViennaViennaAustria
| | - Kees Spruijt
- Holland Proton Therapy CenterDelftThe Netherlands
| | - Joël Herault
- Departement of Radiation OncologyCentre Antoine LacassagneNiceFrance
| | | | - Jens Heufelder
- Helmholtz‐Zentrum Berlin für Materialien und EnergieBerlinGermany
- Department of OphthalmologyCharité ‐ Universitätsmedizin BerlinBerlinGermany
| | - Jan Hrbacek
- Paul Scherrer Institute Center for Proton TherapyVilligenSwitzerland
| | - Tomasz Horwacik
- Institute of Nuclear PhysicsPolish Academy of SciencesKrakówPoland
| | | | - Andrea Denker
- Helmholtz‐Zentrum Berlin für Materialien und EnergieBerlinGermany
| | - Anaïs Gerard
- Departement of Radiation OncologyCentre Antoine LacassagneNiceFrance
| | - Petter Hofverberg
- Departement of Radiation OncologyCentre Antoine LacassagneNiceFrance
| | - Maria Mamalui
- Department of Radiation OncologyUniversity of FloridaGainesvilleFloridaUSA
| | - Roelf Slopsema
- Department of Radiation OncologyEmory Proton Therapy CenterAtlantaGeorgiaUSA
| | | | - Mischa Hoogeman
- Department of RadiotherapyErasmus MC Cancer Institute, University Medical Center RotterdamThe Netherlands
- Holland Proton Therapy CenterDelftThe Netherlands
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5
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Sanchez-Parcerisa D, Sanz-García I, Ibáñez P, España S, Espinosa A, Gutiérrez-Neira C, López A, Vera JA, Mazal A, Fraile LM, Udías JM. Radiochromic film dosimetry for protons up to 10 MeV with EBT2, EBT3 and unlaminated EBT3 films. Phys Med Biol 2021; 66. [PMID: 33910190 DOI: 10.1088/1361-6560/abfc8d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/28/2021] [Indexed: 11/12/2022]
Abstract
Passive dosimetry with radiochromic films is widely used in proton radiotherapy, both in clinical and scientific environments, thanks to its simplicity, high spatial resolution and dose-rate independence. However, film under-response for low-energy protons, the so-called linear-energy transfer (LET) quenching, must be accounted and corrected for. We perform a meta-analysis on existing film under-response data with EBT, EBT2 and EBT3 GAFchromic™ films and provide a common framework to integrate it, based on the calculation of dose-averaged LET in the active layer of the films. We also report on direct measurements with the 10 MeV proton beam at the Center for Microanalysis of Materials (CMAM) for EBT2, EBT3 and unlaminated EBT3 films, focusing on the 20-80 keVμm-1LET range, where previous data was scarce. Measured film relative efficiency (RE) values are in agreement with previously reported data from the literature. A model on film RE constructed with combined literature and own experimental values in the 5-80 keVμm-1LET range is presented, supporting the hypothesis of a linear decrease of RE with LET, with no remarkable differences between the three types of films analyzed.
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Affiliation(s)
- Daniel Sanchez-Parcerisa
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.,Sedecal Molecular Imaging, Algete, Madrid, Spain
| | - Irene Sanz-García
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | - Paula Ibáñez
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Samuel España
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.,Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Andrea Espinosa
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Carolina Gutiérrez-Neira
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Centro de Microanálisis de Materiales (CMAM), Universidad Autónoma de Madrid, Spain.,ALBA Synchrotron Light Source (CELLS-ALBA), Cerdanyola del Vallès, Barcelona, Spain
| | - Alfonso López
- Dept. de Radiofísica y Protección Radiológica, Hospital de Fuenlabrada, Madrid, Spain
| | - Juan Antonio Vera
- Centro de Protonterapia de Quirónsalud, Pozuelo de Alarcón, Madrid, Spain
| | - Alejandro Mazal
- Centro de Protonterapia de Quirónsalud, Pozuelo de Alarcón, Madrid, Spain
| | - Luis Mario Fraile
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - José Manuel Udías
- Grupo de Física Nuclear, EMFTEL and IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
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6
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Niroomand‐Rad A, Chiu‐Tsao S, Grams MP, Lewis DF, Soares CG, Van Battum LJ, Das IJ, Trichter S, Kissick MW, Massillon‐JL G, Alvarez PE, Chan MF. Report of AAPM Task Group 235 Radiochromic Film Dosimetry: An Update to TG‐55. Med Phys 2020; 47:5986-6025. [DOI: 10.1002/mp.14497] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022] Open
Affiliation(s)
| | | | | | | | | | | | - Indra J. Das
- Radiation Oncology Northwestern University Memorial Hospital Chicago IL USA
| | - Samuel Trichter
- New York‐Presbyterian HospitalWeill Cornell Medical Center New York NY USA
| | | | - Guerda Massillon‐JL
- Instituto de Fisica Universidad Nacional Autonoma de Mexico Mexico City Mexico
| | - Paola E. Alvarez
- Imaging and Radiation Oncology Core MD Anderson Cancer Center Houston TX USA
| | - Maria F. Chan
- Memorial Sloan Kettering Cancer Center Basking Ridge NJ USA
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7
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Moftah B, Aldelaijan S, Shehadeh M, Alzorkany F, Alrumayan F, Alsbeih G, Alshabanah M, Seuntjens J, Tomic N, Devic S. Calibration of MTT assay in proton beams using radiochromic films. Phys Med 2020; 77:146-153. [PMID: 32861190 DOI: 10.1016/j.ejmp.2020.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/31/2020] [Accepted: 08/04/2020] [Indexed: 10/23/2022] Open
Abstract
PURPOSE This study provides methodology of calibrating as well as controlling the output for an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) colorimetric assay irradiated in a low energy proton beam using EBT3-model GAFCHROMICTM film, without correcting for quenching effect. METHODS A calibrated Markus ionization chamber was used to measure the depth dose and beam output for 26.5 MeV protons produced by a CS30 cyclotron. A time-controlled aluminum cylinder was added in front of the horizontal beam-exit serving as a radiation shutter. Following the TRS-398 reference dosimetry protocol for proton beams, the output was calibrated in water at a reference depth of 3 mm. EBT3 film was calibrated for doses up to 8 Gy at the same depth. To verify the dose distribution for each 96-well MTT assay plate, EBT3 film was placed at the reference depth during irradiation and cell doses were scaled by measured percent depth dose (PDD) data. RESULTS The radiochromic film dosimetry system in this study provides dose measurements with an uncertainty better than 3.3% for doses higher than 1 Gy. From a single exposure and utilizing the Gaussian shape of the beam, multiple dose points can be obtained within different wells of the same plate ranging from 6.9 Gy (sigma ∼4%) in the central well, and 2 Gy (sigma ∼8%) for wells positioned closer to the periphery. CONCLUSIONS We described a methodology for radiochromic film-based dose monitoring system, using low-energy protons, which can be used for the MTT assay in any proton beam, except within Bragg peak region.
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Affiliation(s)
- B Moftah
- Radiation Physics Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia; Medical Physics Unit, McGill University, Montréal, Québec, Canada
| | - S Aldelaijan
- Radiation Physics Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - M Shehadeh
- Radiation Physics Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - F Alzorkany
- Radiation Physics Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - F Alrumayan
- Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - G Alsbeih
- Radiation Biology Section, Biomedical Physics Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - M Alshabanah
- Oncology Centre, King Faisal Specialist Hospital & Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - J Seuntjens
- Medical Physics Unit, McGill University, Montréal, Québec, Canada; Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - N Tomic
- Medical Physics Unit, McGill University, Montréal, Québec, Canada; Department of Radiation Oncology, Jewish General Hospital, Montréal, Québec, Canada
| | - S Devic
- Medical Physics Unit, McGill University, Montréal, Québec, Canada; Department of Radiation Oncology, Jewish General Hospital, Montréal, Québec, Canada.
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8
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Resch AF, Heyes PD, Fuchs H, Bassler N, Georg D, Palmans H. Dose- rather than fluence-averaged LET should be used as a single-parameter descriptor of proton beam quality for radiochromic film dosimetry. Med Phys 2020; 47:2289-2299. [PMID: 32166764 PMCID: PMC7318138 DOI: 10.1002/mp.14097] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/24/2020] [Accepted: 02/05/2020] [Indexed: 11/06/2022] Open
Abstract
PURPOSE The dose response of Gafchromic EBT3 films exposed to proton beams depends on the dose, and additionally on the beam quality, which is often quantified with the linear energy transfer (LET) and, hence, also referred to as LET quenching. Fundamentally different methods to determine correction factors for this LET quenching effect have been reported in literature and a new method using the local proton fluence distribution differential in LET is presented. This method was exploited to investigate whether a more practical correction based on the dose- or fluence-averaged LET is feasible in a variety of clinically possible beam arrangements. METHODS The relative effectiveness (RE) was characterized within a high LET spread-out Bragg peak (SOBP) in water made up by the six lowest available energies (62.4-67.5 MeV, configuration " b 1 ") resulting in one of the highest clinically feasible dose-averaged LET distributions. Additionally, two beams were measured where a low LET proton beam (252.7 MeV) was superimposed on " b 1 ", which contributed either 50% of the initial particle fluence or 50% of the dose in the SOBP, referred to as configuration " b 2 " and " b 3 ," respectively. The proton LET spectrum was simulated with GATE/Geant4 at all measurement positions. The net optical density change differential in LET was integrated over the local proton spectrum to calculate the net optical density and therefrom the beam quality correction factor. The LET dependence of the film response was accounted for by an LET dependence of one of the three parameters in the calibration function and was determined from inverse optimization using measurement " b 1 ." This method was then validated on the measurements of " b 2 " and " b 3 " and subsequently used to calculate the RE at 900 positions in nine clinically relevant beams. The extrapolated RE set was used to derive a simple linear correction function based on dose-averaged LET ( L d ) and verify the validity in all points of the comprehensive RE set. RESULTS The uncorrected film dose deviated up to 26% from the reference dose, whereas the corrected film dose agreed within 3% in all three beams in water (" b 1 ", " b 2 " and " b 3 "). The LET dependence of the calibration function started to strongly increase around 5 keV/μm and flatten out around 30 keV/μm. All REs calculated from the proton fluence in the nine simulated beams could be approximated with a linear function of dose-averaged LET (RE = 1.0258-0.0211 μm/keV L d ). However, no functional relationship of RE- and fluence-averaged LET could be found encompassing all beam energies and modulations. CONCLUSIONS The film quenching was found to be nonlinear as a function of proton LET as well as of the dose-averaged LET. However, the linear relation of RE on dose-averaged LET was a good approximation in all cases. In contrast to dose-averaged LET, fluence-averaged LET could not describe the RE when multiple beams were applied.
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Affiliation(s)
- Andreas Franz Resch
- Division Medical Radiation Physics, Department of Radiotherapy, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/AKH Wien, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Paul David Heyes
- Division Medical Radiation Physics, Department of Radiotherapy, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/AKH Wien, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Hermann Fuchs
- Division Medical Radiation Physics, Department of Radiotherapy, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/AKH Wien, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Niels Bassler
- Medical Radiation Physics, Department of Physics, Stockholm University, Stockholm, Sweden.,Department of Oncology and Pathology, Medical Radiation Physics, Karolinska Institutet, Stockholm, Sweden.,Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Dietmar Georg
- Division Medical Radiation Physics, Department of Radiotherapy, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/AKH Wien, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Hugo Palmans
- MedAustron Ion Therapy Centre/EBG MedAustron, Marie-Curie-Straße 5, 2700, Wiener Neustadt, Austria.,Medical Radiation Science, National Physical Laboratory, Hampton Road, TW11 0LW, Teddington, United Kingdom
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9
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Massillon-Jl G, Cabrera-Santiago A. Dose-average linear energy transfer of electrons released in liquid water and LiF:Mg,Ti by low-energy x-rays, 137Cs and 60Co gamma. Biomed Phys Eng Express 2020; 6:037001. [PMID: 33438680 DOI: 10.1088/2057-1976/ab78db] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
For many years, track-average linear energy transfer (LET), [Formula: see text] has been used to quantify the radiation-induced phenomena in biological and physical systems. However, due to the need for including into the radiotherapy treatment planning system, parameters that are clinical and biologically relevant, a precise knowledge of the dose-average LET, [Formula: see text] becomes essential. Besides, several dosimetric studies have revealed that [Formula: see text] is fundamental to describe the dosimeter's response induced by photons. The most important data sets publicly available for [Formula: see text] of electron generated by photons are those reported for measurements performed in methane-based tissue-equivalent gas. However, comparing to liquid water, the electron spectra generated by low photon energy might not be similar due to the photoelectric effect. Thus, this work aimed at investigating the [Formula: see text] of electron spectra generated in liquid water and LiF:Mg,Ti by ten x-ray beams from 20 kV to 300 kV, 137Cs and 60Co gamma. The results suggest that [Formula: see text] is more sensitive to the surrounding environment than [Formula: see text] and consequently, it might be a more appropriate parameter to quantify the radiation effect and damage in matter induced by photons. Besides, good agreement (6% to 12% differences versus 10% to 15% uncertainties in the experiments) was observed between the data obtained in this work for liquid water and the experimental values published for methane-based tissue-equivalent gas at energies above 60 keV. Whereas at lowest energies, the minimum difference is around 18% which can be associated to the difference between the two media.
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Affiliation(s)
- G Massillon-Jl
- Instituto de Física, Universidad Nacional Autónoma de México, 04510 Coyoacan Mexico City, Mexico
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10
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Track and dose-average LET dependence of Gafchromic EBT3 and MD-V3 films exposed to low-energy photons. Sci Rep 2020; 10:2361. [PMID: 32047227 PMCID: PMC7012855 DOI: 10.1038/s41598-020-59233-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 01/28/2020] [Indexed: 11/25/2022] Open
Abstract
Gafchromic films are widely used in radiotherapy using photons, electrons and protons. Dosimetric characteristics of the films in terms of beam-quality is of great importance for a better evaluation of the absorbed-dose in the clinic. In proton-therapy, film’s response has been reported in terms of track-average, LΔ,T, or dose-average, LΔ,D, linear energy transfer (LET), concluding that LΔ,D is a more reliable parameter than LΔ,T. Nonetheless, in photon-beams, the film’s response is generally scrutinised in terms of photon-energy. This work aimed at investigating, the total (TEF) and secondary (SE) electron fluence produced in EBT3 and MD-V3 films exposed to 20 kV-160 kV x-ray and 60Co beams and their corresponding LΔ,T and LΔ,D to determine their influence on the film’s relative-efficiency, REFilm. Regardless the film-model, at energies below 100 keV, LΔ,D for TEF are about 1.7 to 2.5 times those of LΔ,T while for SE they are relatively similar (8–29%). For 60Co-gamma, LΔ,D for TEF and SE are approximately 9 and 4 times LΔ,T, respectively, which implies that LΔ,D is more important for high-photon energies. Independent of the electron-fluence and film-model, REFilm is almost constant at low average-LET, rapidly increases and thereafter steadily rises with average-LET. The REFilm−LET curve indicated that LΔ,D is more sensitive to small change than LΔ,T and if it is evaluated for SE, it would even be more appropriate to better describing the dosimeter response induced by photons in terms of ionization-density instead of LΔ,T for TEF, as generally done. Based on these results, once can conclude that the effect of the average-LET on the film’s response should be considered when use for clinical-dosimetry using photons and not only the energy.
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11
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Vallières S, Bienvenue C, Puyuelo-Valdes P, Salvadori M, d'Humières E, Schiettekatte F, Antici P. Low-energy proton calibration and energy-dependence linearization of EBT-XD radiochromic films. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:083301. [PMID: 31472601 DOI: 10.1063/1.5109644] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/11/2019] [Indexed: 06/10/2023]
Abstract
In this work, we calibrate the newly developed EBT-XD radiochromic films (RCFs) manufactured by Gafchromictm using protons in the energy range of 4-10 MeV. Irradiation was performed on the 2 × 6 MV tandem linear accelerator located at the Université de Montréal. The RCFs were digitized using an Epson Perfection V700 flatbed scanner using both the red-green-blue and grayscale channels. The proton fluences were measured with Faraday cups calibrated in absolute terms. The linear energy transfer function within the active layer of the films was calculated using the mass stopping power tables coming from the PSTAR database from the National Institute of Standards and Technology (NIST) to allow retrieval of the deposited dose. We find that the calibration curves for 7 and 10 MeV protons are nearly equivalent. The 4 MeV calibration curves exhibit a quenching effect due to the Bragg peak that falls close to the active layer. A linearization of this energy dependence was developed using a semiempirical parametric model to allow the generation of calibration curves for any incident proton energy within the present range. Excellent correspondence (<5% dose difference for the same netOD) of the 10 MeV calibration curves was noted when compared to existing high-energy proton (148.2 MeV) calibration curves reported in the literature. Our calibration extends the range of operation of EBT-XD films to low-energy proton beam dosimetry.
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Affiliation(s)
- S Vallières
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1P7, Canada
| | - C Bienvenue
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1P7, Canada
| | - P Puyuelo-Valdes
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1P7, Canada
| | - M Salvadori
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1P7, Canada
| | - E d'Humières
- CELIA, University of Bordeaux, 351 Cours de la Libération, Talence 33400, France
| | - F Schiettekatte
- University of Montreal, 2900 Boulevard Edouard-Montpetit, Montréal, Quebec H3T 1J4, Canada
| | - P Antici
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1P7, Canada
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12
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Anderson SE, Grams MP, Wan Chan Tseung H, Furutani KM, Beltran CJ. A linear relationship for the LET-dependence of Gafchromic EBT3 film in spot-scanning proton therapy. ACTA ACUST UNITED AC 2019; 64:055015. [DOI: 10.1088/1361-6560/ab0114] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Gambarini G, Bettega D, Camoni G, Barzon G, Bettinelli L, Giove D, Carrara M, Mirandola A, Ciocca M. Development of a procedure for quenching-effect correction in images of absorbed dose from protons or carbon ions acquired with Gafchromic EBT3 films. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2018.06.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Influence of Linear Energy Transfer on the Nucleo-shuttling of the ATM Protein: A Novel Biological Interpretation Relevant for Particles and Radiation. Int J Radiat Oncol Biol Phys 2018; 103:709-718. [PMID: 30342967 DOI: 10.1016/j.ijrobp.2018.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 09/19/2018] [Accepted: 10/08/2018] [Indexed: 11/22/2022]
Abstract
PURPOSE Linear energy transfer (LET) plays an important role in radiation response. Recently, the radiation-induced nucleo-shuttling of ATM from cytoplasm to the nucleus was shown to be a major event of the radiation response that permits a normal DNA double-strand break (DSB) recognition and repair. Here, we aimed to verify the relevance of the ATM nucleo-shuttling model for high-LET particles and various radiation types. METHODS AND MATERIALS ATM- and H2AX-immunofluorescence was used to assess the number of recognized and unrepaired DSB in quiescent fibroblast cell lines exposed to x-rays, γ-rays, 9- and 12-MeV electrons, 3- and 65-MeV protons and 75-MeV/u carbon ions. RESULTS The rate of radiation-induced ATM nucleo-shuttling was found to be specific to each radiation type tested. By increasing the permeability of the nuclear membrane with statin and bisphosphonates, 2 fibroblast cell lines exposed to high-LET particles were shown to be protected by an accelerated ATM nucleo-shuttling. CONCLUSIONS Our findings are in agreement with the conclusion that LET and the radiation/particle type influence the formation of ATM monomers in cytoplasm that are required for DSB recognition. A striking analogy was established between the DSB repair kinetics of radioresistant cells exposed to high-LET particles and that of several radiosensitive cells exposed to low-LET radiation. Our data show that the nucleo-shuttling of ATM provides crucial elements to predict radiation response in human quiescent cells, whatever the LET value and their radiosensitivity.
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Chan MF, Chen CC, Shi C, Li J, Tang X, Li X, Mah D. Patient-Specific QA of Spot-Scanning Proton Beams using Radiochromic Film. ACTA ACUST UNITED AC 2017; 6:111-123. [PMID: 28620561 DOI: 10.4236/ijmpcero.2017.62011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Radiochromic film for spot-scanning QA provides high spatial resolution and efficiency gains from one-shot irradiation for multiple depths. However, calibration can be a tedious procedure which may limit widespread use. Moreover, since there may be an energy dependence, which manifests as a depth dependence, this may require additional measurements for each patient. We present a one-scan protocol to simplify the procedure. A calibration using an EBT3 film, exposed by a 6-level step-wedge plan on a Proteus®PLUS proton system (IBA, Belgium), was performed at depths of 18, 20, 24cm using Plastic Water® (CIRS, Norfolk, VA). The calibration doses ranged from 65-250 cGy(RBE) (relative biological effectiveness) for proton energies of 170-200 MeV. A clinical prostate+nodes plan was used for validation. The planar doses at selected depths were measured with EBT3 films and analyzed using One-scan protocol (one-scan digitization of QA film and at least one film exposed to a known dose). The gamma passing rates, dose-difference maps, and profiles of 2D planar doses measured with EBT3 film and IBA MatriXX-PT, versus the RayStation TPS calculations were analyzed and compared. The EBT3 film measurement results matched well with the TPS calculation data with an average passing rate of ~95% for 2%/2mm and slightly lower passing rates were obtained from an ion chamber array detector. We were able to demonstrate that the use of a proton step-wedge provided clinically acceptable results and minimized variations between film-scanner orientation, inter-scan, and scanning conditions. Furthermore, for relative dosimetry (calibration is not done at the time of experiment) it could be derived from no more than two films exposed to known doses (one could be zero) for rescaling the master calibration curve at each depth. The sensitivity of the calibration to depth variations has been explored. One-scan protocol results appear to be comparable to that of the ion chamber array detector. The use of a proton step-wedge for calibration of EBT3 film potentially increases efficiency in patient-specific QA of proton beams.
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Affiliation(s)
- Maria F Chan
- Dept. of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Chin-Cheng Chen
- Dept. of Radiation Physics, ProCure Proton Center, Somerset, NJ
| | - Chengyu Shi
- Dept. of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Jingdong Li
- Dept. of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Xiaoli Tang
- Dept. of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Xiang Li
- Dept. of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Dennis Mah
- Dept. of Radiation Physics, ProCure Proton Center, Somerset, NJ
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16
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Borowicz DM, Malicki J, Mytsin G, Shipulin K. Dose distribution at the Bragg peak: Dose measurements using EBT and RTQA gafchromic film set at two positions to the central beam axis. Med Phys 2017; 44:1538-1544. [PMID: 28196271 DOI: 10.1002/mp.12159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 01/23/2017] [Accepted: 02/05/2017] [Indexed: 11/08/2022] Open
Abstract
AIM To evaluate the impact of radiochromic film positioning relative to the central beam axis (CAX) in proton beam therapy. Secondarily, to compare the dosimetric measurements obtained by RTQA and EBT film and to compare these to the doses calculated by the treatment planning system (TPS). METHODS The EBT and RTQA dosimetric radiochromic films were immersed in a water phantom and irradiated with a proton beam. The films were placed parallel to the CAX and at a 5° angle on the horizontal plane to assess the effect of film inclination on Bragg peak profiles. Calibration was performed by irradiating small pieces of film at doses ranging from 0.0 Gy to 3.5 Gy in increments of 0.5 Gy. The TPS was used to create treatment plans for two different geometrical targets (cylindrical and cuboidal). After irradiation, all film pieces were scanned on a flatbed scanner and red channel data were extracted from the 48-bit RGB images using ImageJ, Photoshop, Origin8, and Excel software. The dose distributions from the irradiated films were compared to the dose obtained from the TPS. Bragg peak profiles were abstracted from the irradiated films and compared. RESULTS The dosimetric measurements obtained by both EBT and RTQA positioned at a 5° to the CAX closely matched the dose calculated by the TPS for the cylindrical target. In contrast, dose distributions measured in the cuboidal targets were less precise. Gamma index (GI) values (3%/3 mm acceptance criteria for isodose >90% of dose) were 99.8% and 93% for EBT film placed at a 5° angle versus 47.1% and 80.8% for EBT film parallel to the beam. The dosimetric measurements in RTQA film positioned parallel to the CAX showed GI values with <27% agreement with the TPS-calculated dose. CONCLUSION Our finding show that RTQA film can be used to accurately measure doses in the proton beam at the region of Bragg peak; however, to obtain the most accurate readings, the film should be positioned at a small angle to the CAX.
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Affiliation(s)
- Dorota Maria Borowicz
- Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland.,Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980, Dubna, Moscow region, Russia
| | - Julian Malicki
- Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland.,Electroradiology Department, University of Medical Sciences, Poznan, Poland
| | - Gennady Mytsin
- Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980, Dubna, Moscow region, Russia
| | - Konstantin Shipulin
- Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980, Dubna, Moscow region, Russia
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17
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Development of simple high-precision two-dimensional dose-distribution measurement method for proton beam therapy using imaging plate and EBT3. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2016; 39:687-96. [PMID: 27470695 DOI: 10.1007/s13246-016-0464-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/12/2016] [Indexed: 10/21/2022]
Abstract
Although there are several two-dimensional (2D) dose-distribution measurement methods using proton beam therapy, they all have drawbacks; hence, there is no standard method established worldwide. The purpose of this study was to develop a simple, high-precision 2D distribution measurement method for proton beam therapy that uses an imaging plate and EBT3. First, we expanded the maximum readable dose (saturation dose) in the imaging plate. The method involves (i) the control of the fading phenomenon by an annealing process and (ii) the control of the photostimulated luminescence (PSL) phenomenon using a longpass filter (LPF). In method (i), upon heating at 80 °C, the PSL became 0.485 times the room temperature, and in method (ii), we attenuated the PSL by a factor of 0.245 using an LPF. Thus, by combining methods (i) and (ii), we expanded the saturation dose to 2 Gy. Thus, it was possible to measure the imaging plate and EBT3 in the same dose range. We simultaneously measured the percent depth dose using imaging plate and EBT3. We defined a correction factor to match the measured values-which had a reduced sensitivity because of the linear energy transfer (LET) dependence of the imaging plate and EBT3-with reference data and developed a correction factor function. Subsequently, by defining the relative LET dependence of imaging plate and EBT3 as the relative sensitivity and converting the relationship imaging plate between the relative sensitivity and correction factor into a function, we obtained a sensitivity-correction function. By employing this function, measurements with the same accuracy as the reference data were performed using the imaging plate and EBT3.
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18
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Rasouli FS, Farhad Masoudi S, Keshazare S, Jette D. Effect of elemental compositions on Monte Carlo dose calculations in proton therapy of eye tumors. Radiat Phys Chem Oxf Engl 1993 2015. [DOI: 10.1016/j.radphyschem.2015.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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19
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Vadrucci M, Esposito G, Ronsivalle C, Cherubini R, Marracino F, Montereali RM, Picardi L, Piccinini M, Pimpinella M, Vincenti MA, De Angelis C. Calibration of GafChromic EBT3 for absorbed dose measurements in 5 MeV proton beam and 60
Co γ-rays. Med Phys 2015; 42:4678-84. [DOI: 10.1118/1.4926558] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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20
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Yeo IJ, Teran A, Ghebremedhin A, Johnson M, Patyal B. Radiographic film dosimetry of proton beams for depth-dose constancy check and beam profile measurement. J Appl Clin Med Phys 2015; 16:5402. [PMID: 26103499 PMCID: PMC5690120 DOI: 10.1120/jacmp.v16i3.5402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/28/2015] [Accepted: 12/21/2014] [Indexed: 11/23/2022] Open
Abstract
Radiographic film dosimetry suffers from its energy dependence in proton dosimetry. This study sought to develop a method of measuring proton beams by the film and to evaluate film response to proton beams for the constancy check of depth dose (DD). It also evaluated the film for profile measurements. To achieve this goal, from DDs measured by film and ion chamber (IC), calibration factors (ratios of dose measured by IC to film responses) as a function of depth in a phantom were obtained. These factors imply variable slopes (with proton energy and depth) of linear characteristic curves that relate film response to dose. We derived a calibration method that enables utilization of the factors for acquisition of dose from film density measured at later dates by adapting to a potentially altered processor condition. To test this model, the characteristic curve was obtained by using EDR2 film and in-phantom film dosimetry in parallel with a 149.65 MeV proton beam, using the method. An additional validation of the model was performed by concurrent film and IC measurement perpendicular to the beam at various depths. Beam profile measurements by the film were also evaluated at the center of beam modulation. In order to interpret and ascertain the film dosimetry, Monte Carlos simulation of the beam was performed, calculating the proton fluence spectrum along depths and off-axis distances. By multiplying respective stopping powers to the spectrum, doses to film and water were calculated. The ratio of film dose to water dose was evaluated. Results are as follows. The characteristic curve proved the assumed linearity. The measured DD approached that of IC, but near the end of the spread-out Bragg peak (SOBP), a spurious peak was observed due to the mismatch of distal edge between the calibration and measurement films. The width of SOBP and the proximal edge were both reproducible within a maximum of 5mm; the distal edge was reproducible within 1 mm. At 5 cm depth, the dose was reproducible within 10%. These large discrepancies were identified to have been contributed by film processor uncertainty across a layer of film and the misalignment of film edge to the frontal phantom surface. The deviations could drop from 5 to 2 mm in SOBP and from 10% to 4.5% at 5 cm depth in a well-controlled processor condition(i.e., warm up). In addition to the validation of the calibration method done by the DD measurements, the concurrent film and IC measurement independently validated the model by showing the constancy of depth-dependent calibration factors. For profile measurement, the film showed good agreement with ion chamber measurement. In agreement with the experimental findings, computationally obtained ratio of film dose to water dose assisted understanding of the trend of the film response by revealing relatively large and small variances of the response for DD and beam profile measurements, respectively. Conclusions are as follows. For proton beams, radiographic film proved to offer accurate beam profile measurements. The adaptive calibration method proposed in this study was validated. Using the method, film dosimetry could offer reasonably accurate DD constancy checks, when provided with a well-controlled processor condition. Although the processor warming up can promote a uniform processing across a single layer of the film, the processing remains as a challenge.
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21
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Reinhardt S, Würl M, Greubel C, Humble N, Wilkens JJ, Hillbrand M, Mairani A, Assmann W, Parodi K. Investigation of EBT2 and EBT3 films for proton dosimetry in the 4-20 MeV energy range. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2015; 54:71-79. [PMID: 25572031 DOI: 10.1007/s00411-014-0581-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
Radiochromic films such as Gafchromic EBT2 or EBT3 films are widely used for dose determination in radiation therapy because they offer a superior spatial resolution compared to any other digital dosimetric 2D detector array. The possibility to detect steep dose gradients is not only attractive for intensity-modulated radiation therapy with photons but also for intensity-modulated proton therapy. Their characteristic dose rate-independent response makes radiochromic films also attractive for dose determination in cell irradiation experiments using laser-driven ion accelerators, which are currently being investigated as future medical ion accelerators. However, when using these films in ion beams, the energy-dependent dose response in the vicinity of the Bragg peak has to be considered. In this work, the response of these films for low-energy protons is investigated. To allow for reproducible and background-free irradiation conditions, the films were exposed to mono-energetic protons from an electrostatic accelerator, in the 4-20 MeV energy range. For comparison, irradiation with clinical photons was also performed. It turned out that in general, EBT2 and EBT3 films show a comparable performance. For example, dose-response curves for photons and protons with energies as low as 11 MeV show almost no differences. However, corrections are required for proton energies below 11 MeV. Care has to be taken when correction factors are related to an average LET from depth-dose measurements, because only the dose-averaged LET yields similar results as obtained in mono-energetic measurements.
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Affiliation(s)
- S Reinhardt
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians Universität München, 85748, Garching, Germany.
| | - M Würl
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians Universität München, 85748, Garching, Germany
| | - C Greubel
- Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, 85779, Neubiberg, Germany
| | - N Humble
- Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Munich, Germany
| | - J J Wilkens
- Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Munich, Germany
| | - M Hillbrand
- Rinecker Proton Therapy Center, Munich, Germany
| | - A Mairani
- Medical Physics Unit CNAO Foundation, Pavia, Italy
| | - W Assmann
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians Universität München, 85748, Garching, Germany
| | - K Parodi
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians Universität München, 85748, Garching, Germany
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22
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Subiel A, Moskvin V, Welsh GH, Cipiccia S, Reboredo D, Evans P, Partridge M, DesRosiers C, Anania MP, Cianchi A, Mostacci A, Chiadroni E, Di Giovenale D, Villa F, Pompili R, Ferrario M, Belleveglia M, Di Pirro G, Gatti G, Vaccarezza C, Seitz B, Isaac RC, Brunetti E, Wiggins SM, Ersfeld B, Islam MR, Mendonca MS, Sorensen A, Boyd M, Jaroszynski DA. Dosimetry of very high energy electrons (VHEE) for radiotherapy applications: using radiochromic film measurements and Monte Carlo simulations. Phys Med Biol 2014; 59:5811-29. [PMID: 25207591 DOI: 10.1088/0031-9155/59/19/5811] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Very high energy electrons (VHEE) in the range from 100-250 MeV have the potential of becoming an alternative modality in radiotherapy because of their improved dosimetry properties compared with MV photons from contemporary medical linear accelerators. Due to the need for accurate dosimetry of small field size VHEE beams we have performed dose measurements using EBT2 Gafchromic® film. Calibration of the film has been carried out for beams of two different energy ranges: 20 MeV and 165 MeV from conventional radio frequency linear accelerators. In addition, EBT2 film has been used for dose measurements with 135 MeV electron beams produced by a laser-plasma wakefield accelerator. The dose response measurements and percentage depth dose profiles have been compared with calculations carried out using the general-purpose FLUKA Monte Carlo (MC) radiation transport code. The impact of induced radioactivity on film response for VHEEs has been evaluated using the MC simulations. A neutron yield of the order of 10(-5) neutrons cm(-2) per incident electron has been estimated and induced activity due to radionuclide production is found to have a negligible effect on total dose deposition and film response. Neutron and proton contribution to the equivalent doses are negligible for VHEE. The study demonstrates that EBT2 Gafchromic film is a reliable dosimeter that can be used for dosimetry of VHEE. The results indicate an energy-independent response of the dosimeter for 20 MeV and 165 MeV electron beams and has been found to be suitable for dosimetry of VHEE.
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Affiliation(s)
- A Subiel
- Department of Physics, Scottish Universities Physics Alliance, University of Strathclyde, Glasgow G4 0NG, UK
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Fiorini F, Kirby D, Thompson J, Green S, Parker D, Jones B, Hill M. Under-response correction for EBT3 films in the presence of proton spread out Bragg peaks. Phys Med 2014; 30:454-61. [DOI: 10.1016/j.ejmp.2013.12.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 11/24/2013] [Accepted: 12/30/2013] [Indexed: 11/25/2022] Open
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Carnicer A, Angellier G, Thariat J, Sauerwein W, Caujolle JP, Hérault J. Quantification of dose perturbations induced by external and internal accessories in ocular proton therapy and evaluation of their dosimetric impact. Med Phys 2014; 40:061708. [PMID: 23718587 DOI: 10.1118/1.4807090] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Proton scattering on beam shaping devices and protons slowing down on media with different densities within the treatment volume may produce dose perturbations and range variations that are not predicted by treatment planning systems. The aim of this work was to assess the dosimetric impact of elements present in ocular proton therapy treatments that may disturb the prescribed treatment plan. Both distal beam shaping devices and intraocular elements were considered. METHODS A wedge filter, tantalum fiducial marker, hemispherical compensator, two intraocular endotamponades (densities 0.97 and 1.92 g cm(-3)) and an intraocular eye lens (IOL) were considered in the study. For these elements, longitudinal dose distributions were measured and∕or calculated in water in beam alignment for a clinical spread-out Bragg peak. Under the same conditions, the unperturbed dose distributions were similarly measured and∕or calculated in the absence of the element. The dosimetric impact was assessed by comparison of unperturbed and perturbed dose distributions. Measurements and calculations were carried out with two methods. Measurements are based on EBT3 films with dedicated software, which makes use of a calibration curve and correction for the quenching effect. Calculations are based on the Monte Carlo (MC) code MCNPX and reproduce the experimental conditions. Both dose maps are obtained with a resolution of 300 dpi. RESULTS The degree of disturbance of distal beam shaping devices is low for the wedge filter (2% overdose ripple all along the central axis) and moderate for the hemispherical compensator (two bands of variable overdose of up to 10% downstream the compensator lateral edges and -5% underdose on the plateau at off-axis distance of 5 cm). Tantalum clips produce important dose shadows (-20% behind the clip parallel to the beam and range reduction of 1.1 mm) and bands of overdose (15%). The presence of endotamponades modifies the dose distribution very significantly (-5% underdose on the plateau and 3 mm range prolongation for the tamponade with density 0.97 g cm(-3) and -15% underdose on plateau and 8 mm range reduction for that with density 1.92 g cm(-3)). No dose perturbations were found for the IOL. The high performance of EBT3 film and MC tools used was confirmed and good agreement was found between them (percentage of pixels passing the gamma test >87%). CONCLUSIONS The degree of disturbance by external beam shaping devices remains low in ocular proton therapy and can be reduced by bringing accessories closer to the eye. Tantalum fiducial markers must be located in such a way that dose perturbation is not projected on the tumor. The treatment of patients with intraocular endotamponades must be carefully managed. It is fundamental that radiation oncologists and medical physicists are informed about the presence of such substances prior to the treatment.
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Affiliation(s)
- A Carnicer
- Centre Antoine Lacassagne, Cyclotron Biomédical, 227 Avenue de la Lanterne, 06200 Nice, France
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Carnicer A, Angellier G, Gérard A, Garnier N, Dubois C, Amblard R, Hérault J. Development and validation of radiochromic film dosimetry and Monte Carlo simulation tools for acquisition of absolute, high-spatial resolution longitudinal dose distributions in ocular proton therapy. RADIAT MEAS 2013. [DOI: 10.1016/j.radmeas.2013.06.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Perles LA, Mirkovic D, Anand A, Titt U, Mohan R. LET dependence of the response of EBT2 films in proton dosimetry modeled as a bimolecular chemical reaction. Phys Med Biol 2013; 58:8477-91. [DOI: 10.1088/0031-9155/58/23/8477] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Uehara R, Tachibana H, Ito Y, Yoshino S, Matsubayashi F, Sato T. [A practical procedure to improve the accuracy of radiochromic film dosimetry: a integration with a correction method of uniformity correction and a red/blue correction method]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2013; 69:617-31. [PMID: 23782774 DOI: 10.6009/jjrt.2013_jsrt_69.6.617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It has been reported that the light scattering could worsen the accuracy of dose distribution measurement using a radiochromic film. The purpose of this study was to investigate the accuracy of two different films, EDR2 and EBT2, as film dosimetry tools. The effectiveness of a correction method for the non-uniformity caused from EBT2 film and the light scattering was also evaluated. In addition the efficacy of this correction method integrated with the red/blue correction method was assessed. EDR2 and EBT2 films were read using a flatbed charge-coupled device scanner (EPSON 10000G). Dose differences on the axis perpendicular to the scanner lamp movement axis were within 1% with EDR2, but exceeded 3% (Maximum: +8%) with EBT2. The non-uniformity correction method, after a single film exposure, was applied to the readout of the films. A corrected dose distribution data was subsequently created. The correction method showed more than 10%-better pass ratios in dose difference evaluation than when the correction method was not applied. The red/blue correction method resulted in 5%-improvement compared with the standard procedure that employed red color only. The correction method with EBT2 proved to be able to rapidly correct non-uniformity, and has potential for routine clinical IMRT dose verification if the accuracy of EBT2 is required to be similar to that of EDR2. The use of red/blue correction method may improve the accuracy, but we recommend we should use the red/blue correction method carefully and understand the characteristics of EBT2 for red color only and the red/blue correction method.
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Affiliation(s)
- Ryuzo Uehara
- Department of Radiation Oncology, The Cancer Institute Hospital of JFCR
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Gomà C, Andreo P, Sempau J. Spencer–Attix water/medium stopping-power ratios for the dosimetry of proton pencil beams. Phys Med Biol 2013; 58:2509-22. [DOI: 10.1088/0031-9155/58/8/2509] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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